High-Tech Sprayer Zaps Weeds with Less Herbicide

A high-tech sprayer equipped with a light reflectance sensor scours the ground for weeds and kills them with less herbicide than conventional sprayers use, Agricultural Research Service scientists report.

The new device, an eight-row hooded sprayer, uses its sensor to distinguish differences in light reflected from bare soil versus weeds in the area between rows of planted crops. It applies herbicides only where weeds are present. The sprayer was developed for row crops through a Cooperative Research and Development Agreement with Patchen, Inc., of Los Gatos, Calif., and scientists at ARS' Application and Production Technology Research Unit in Stoneville, Miss.

ARS researchers tested the sensor sprayer as part of the Mississippi Delta Management Systems Evaluation Area project, which was begun to study how agricultural production practices affect the water quality of three Mississippi lakes.

Researchers evaluated the weed-sensor spray technology as a way to cut herbicide use for cotton and soybeans grown under conservation tillage. During the 2-year ARS study (1996 and 1997), herbicide savings averaged 78 percent on 105 acres of cotton and 51 percent on 115 acres of soybeans over the two growing seasons.

The scientists say this technology will help farmers by minimizing herbicide use and will cut costs while reducing the environmental impact of agrichemicals on water supplies.

Scientific contact: James E. Hanks, ARS Application and Production Technology Research Unit, Stoneville, Miss., phone (601) 686-5382, fax (601) 636-5372, jhanks@ag.gov.